Watt-hour meter



n Feb. 7, 1939. H, E TREK 2,146,606

WATT-HOUR METER Filed Dec. 23, 1936 Low RESISTANCE couuucma MATERIAL I HIGH RESISTANCE MATERIAL LAG Aouusmznr BY SLIDING MOVEMENT 0F PLATE I? LIGHT LOAD ADJUSTING SCREW CONTROL PIVOTAL MOVEMENT Inventor: Harold E. Tr-ekell,

Attorn e y.

Patented F ch. 7, 1939 f UNITED-j STATES PAT NT T o.1,-". ce7

' WATT-HOUR Marisa I Harold E. Trekell, Beach Bluff, Mass., assignor to General Electric Company, a corporation of New York Application December 23, 1936, Serial Na rmss 6 Claims.

use of a single plate serving as the combined lag 10 and light-load pla-te.

A further object of my invention is to provide an arrangement which permits making either adjustment substantially without affecting the other adjustment.

It is still another object of my invention to provide a mounting arrangement for lag plates serving to compensate for temperature errors of the class varying with power factor.

Other and further objects andadvantages will become apparent as the description proceeds.

In accordance with my invention in its preferred form, I utilize a lag coil or plate stamped from sheet metal and slidablymount it ina frame which is pivoted near the axis of rotation of the meter disk so that angular adjustment of the mounting frame serves to vary the lateral position of the lag plate with respect to the current and potential pole pieces for correcting the lightload torque, and radial adjustment of thelag plate within the frame serves to vary. the amount of magnet flu'x'intercepted-by the lag plate for correcting the amount of lagging provided.

The invention may be understood more readily from the following detailed description when considered in connection with the accompanying drawing and those features of the invention which are believedto be novel and patentable. will be pointed out in the claims appended hereto. In the drawing,'Fig. 1 is a perspective view of a wa thour meter mechanism illustrating one embodimentof my invention with certain portions broken away inorder to show the parts in the interior of the mechanism; and Fig. 2 is an exploded perspective view of the parts making up the lag plate and thelag plate mounting frame. Like reference characters are utilized throughout the drawing to designateilike parts.

' Referring now more in detail to the drawing,

it will be seen that:I have illustrated onlythe actual meter mechanism omitting the register, casing, cover and other parts, since these do not constitute a part-of .the present invention. The

base to which theparts ofthe meter mechanism are attached is shown only fragmentarily and u may consist of a; casting l Ito which is secured a.

field structure I2 preferably consisting of laminations of magnetizable material/and to which are also secured bearings.(not shown) for supporting a shaft l3, carrying a meter rotor in the form of an induction disk 14.

The field structure l2 contains an air gap for the induction disk M. The air gap is formed between the potential magnet I5, the lower end of which is shown broken away for clarity, and a U-shaped current magnet I6. For the purpose or providing the desired laggingbetween the voltage applied to themeter and the magneticflu r produced by the potentialmagnet I5 and also for the purpose of providing sufficient light-load. torque to overcome the bearing friction of the rotor, e lag plate I 1 is providedwhich is. also mounted in the air gap between the potential magnet I5 and the current magnet l6, preferably on the side of the disk l4 toward the current magnet I6. I The plzxe II is referred to for convenience as a lag 20 plate but it will be understood that .-it serves the combined functionof a lag plate'and a lightload plate. I mean to include such a plate or coil for performing these combined functions wherever I use the term "lag plate in the de- 25 scripfion and claims. 7 V

For adjustably supporting the leg plate .I I, a lag plate mounting frame I 8 is provided. The frame l8 may be formed from sheet metal and is provided with an offset earlQ by means of which the 30 frame I8 is pivotally attached to the casting H. Any desired means may be employed for pivotally securing the frame l8 to the casting H, for example, a hole '20 may. be punched in the ear. l9 and a screw 2| may be provided, which is threaded 35 into a suitable projection 22: on the casting H located as closeas practicable to the shaft l3 and the axis of rotation of the disk.

Angular adjustment of the lag plate mounting.

frame l8 may be obtained by means ota. screw 40 23 adapted tobe inserted in an opening l l in a transverse projection 25. ofthe frame 8 and l threaded into thebaseji I. l toidraw theipiroj ection 25 toward the portion '26 of the meter base I I. A

- spring 21 maybe provided for resiliently opposing 4 the action of'the, screw 23' and rotatingframe |,8

in the opposite direction about the pivot screw 2| when the s'creWfZilj'i'sfbackedout. addition to the screw 21, anelongatedslot 28 in the frame 3 and a'clamping screw" 29' threaded intoaf'brdjection. 30in the casting ll may be provided for movably supporting the frame |8. f v

' Although I havedisclo'sed'an arrangement which thevariationin 'light 'load torque, is lobtained by angular adjustmentcf the mounting frame I8 and the variation in the lagging is obtained by sliding the lag plate II within the frame I8, it will be understood that my invention is not limited to this precise arrangement but that I may locate the pivot screw 2| supporting the frame I8 in a suitable position so as to move the lag plate through an arc including the shaft I3 by angular adjustment of the mounting frame I8 for varying the lagging and, in this case, the sliding movement within the frame would serve to vary the light-load torque. If desired, the supporting pivot'2I may also be located on the side of the core I2 away from the shaft I3 whether the arrangement is such that angular adjustment of the mounting frame I8 produces light-load adjustment or lag adjustment.

The lag plate I! may, if desired, be of the type constructed with a suitable amount'of temperature variable reactance integral with the lag plate for the purpose of compensating the meter for temperature errors occurring when the power factor changes. The part of the lag plate providing temperature compensation is not a part of my present invention and this feature may or may not be present without affecting the manner in which lag and light-load adjustment are obtained in my apparatus. Accordingly, the'part of the construction providing temperature compensation will be described only briefly. The temperature variable reactance is produced by means of a negative temperature coeflicient of permeability magnetic'circuit linking the lag plate I I. This circuit may take the form of a piece 3| bent in order to surround partially a portion of the lag plate I I, and a piece 32 secured to the piece 3|. One or both of the pieces 3I"and 32 are composed of material having a negative temperature coefficient of permeability. I have found that satisfactory results may be obtained by utilizing a 29.5 per cent nickel iron alloy for the piece 32 and a ferromagnetic material known by the trade name Armco for the piece 3|.

It will be observed that the central portion 33 of the lag plate I I is cut out to form what may be referred to as a hollow square, which provides a closed electric circuit or loop linking magnetic flux crossing the air gap between the potential magnet I5 and the current magnet I8 of the meter. The width of the plate I1 is such as to cause it to fit-within the frame I8, and the portion 34 of the plate I! may be offset to make the portion 34 of the plate II flush with the frame I8 while permitting the ends 35 of the plate I! to ride under the end136 of the frame I8. A suitable notch 31 is left in the end portion of the frame I8 to accommodate the reactance forming magnetic pieces 3| and 32. One side of the opposite end 38 of the plate I! is of such length as to rest upon the end portion 39 of the frame I8, and a perforated car 40 may be provided at the end 38 on the plate I I having a threaded hole 4| to receive a clamping screw 42 cooperating with an elongated slot 43 on the frame I8 to permit adjusting the position of the plate I! in the frame I8 and securing the plate in the desired position. The parts I l and I8 may be slightly sprung in order to insure that tightening the screw 42 will hold the ends 35 of the plate II up against the end 36 of the frame I8.

It will be understood that the lag plate I! is composed of current-conducting material, such as copper, for example, and-that the lag plate mounting frame I8 is preferably composed of material such as an alloy of copper, zinc and nickel, commercially known as 18% nickel silver, for ex.--

ample, having relatively high electrical resistance in order to avoid shunting the reactance of the lag plate I! and which is substantially nonmagnetic in order to avoid introducing any disturbance in the magnetic field of the field structure I2.

Owing to the fact that the pivotscrew 2| of the frame I8 isat some distance from'the magnets I5 and I6 and relatively closeto the axis of rotation of the disk I4, the frame I8 may be rotated about the screw -2| to make the plate I] more or less unsymmetrical with respect to the current electromagnet I8, thereby producing a greater or lesser shading effect to obtain thedesired adjustment in light-load torque without thereby appreciably affecting the amount of potential flux linked by the plate I1 and thus leaving the lag adjustment substantially unaffected. Likewise,

the plate I! may he slid back and forth within the frame I8 to vary the amount of lagging without any appreciable effect on the shading of the current coils and the light-load torque.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof but I desire to have it understood that the apparatus shown is only illus: trative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, a base for supporting the parts of a watt-hour meter, a field structure attached to said base and having an air gap with current and potential magnets for passing magnetic flux across said air gap, an induction disk the position of said plate in said frame, and means in proximity to said adjusting mechanism f for adjusting theangular position of said frame on said base.

2. In combination, a base for supporting the parts of a watt-hour meter, a field structure attached to said base and having an {air gap with current and potential magnets for passing magnetic flux across said air gap, an induction disk rotatably mounted to travel through said air gap with an axis of rotation at one side of said field structure, a lag plate mounting frame movable in said air gap and having an ear pivotally attached to said base at a point in proximity to the axis of rotation of said disk, and a lag plate slidably mounted on said mounting frame so as to be movable toward and away from the axis of rotation of said disk and securing means in proximity to each other for adjustably fixing the positions cut away, a lag plate composed of sheet metal with the center portion cut out to form a closed electric circuit and having a width corresponding to the inner width of said frame, said frame hav-.

ing an ear at one end thereof for pivotally mounting saidframe, securing means at one end thereof for fixing the angular mounting position of the frame and securing means at .thesame end for slidably attaching said plate to said frame.

4. In combination, a base for Supporting the parts of a watt-hour meter, a field structure attached to said'base and having an air current and potential magnets for passing magnetic flux across said air gap, an induction type rotor rotatably mounted to travel through said air gap and having an axis of rotation at one side of said field structure, a lag plate mounting frame movable in said air gap and having an ear pivotally attached to said base, and a lag plate slidably mounted on said lag plate mounting frame so as to be movable toward and away from the pivot point of said frame, the location of the pivot point of said frame being such that pivoting of the frame produces movement of the lag plate in one path and sliding of the plate within the frame produces movement of the lag plate in a path substantially perpendicular to the first path, but in the same plane as said first path, one of said paths being in such a direction as to include the axis of rotation of said rotor if extended thereto and the other of said paths passing through said air gap.

5. A base for supporting in a given position at one side thereof a watt-hour meter field structure for rotating a disc in a horizontal plane around an axis of rotation beside the position of gap with the field structure, said base having a pivot-holding projection in proximity to the disc axis position under the disc plane, and having a clampingdevice-holding projection on the side of said base away from thefield structure position and under the disc plane, a lag plate mounting frame extending parallel to the disc plane thereunder transversely across the field structure position, having an'ear pivotally attached to said pivotholding projection and having a projection resting on said clamping-device-holding projection, a lag plate mounted slidably within and along said lag plate holding frame, and a clamping device engaging said last mentioned base and frame projections.

6'. A base for supporting in a, given position at one side thereof a watt-hour meter field structure for rotating a disc in a horizontal plane around an axis of rotation beside the position of the field structure, said base having a pivot-holding horizontal-surfaced projection in proximity to the disc axis position under the disc plane, a lag plate mounting frame extending parallel to the disc plane thereunder transversely across the field structure position, having a. fiat ear pivotally attached upon said pivot-holding projection, and a lag plate mounted slidably within and along said lag plate holding frame.

HAROLD E. TREKELL. 

